SampleClock.pde

Clock clock;

void setup() {
  size(200, 200);
  clock = new Clock(width / 2, height / 2, width/2-20);
}

void draw() {
  background(0);
  noFill();
  stroke(255);

  clock.draw();
}

class Clock {
  int x, y, r;

  Clock(int x, int y, int r) {
    this.x = x;
    this.y = y;
    this.r = r;
  }

  void draw() {
    stroke(255);
    noFill();
    strokeWeight(10);
    ellipse(x, x, r*2, r*2);

    int idc_w = 10;
    strokeWeight(10);
    line(x, y - r, x, y - r + idc_w);
    line(x, y + r, x, y + r - idc_w);
    line(x - r, y, x - r + idc_w, y);
    line(x + r, y, x + r - idc_w, y);

    int h = hour();
    int m = minute();
    int s = second();
    
    int s_l = r - 15;
    int m_l = r - 20;
    int h_l = r - 40;
    
    float fh = h / 12.0 + 1.0/12.0/60.0*m;
    strokeWeight(8);
    line(x, y, x + h_l * sin(fh * 2 * PI), y + h_l * -cos(fh * 2 * PI));
    float fm = m / 60.0;
    strokeWeight(5);
    line(x, y, x + m_l * sin(fm * 2 * PI), y + m_l * -cos(fm * 2 * PI));
    float fs = s / 60.0;
    strokeWeight(2);
    line(x, y, x + s_l * sin(fs * 2 * PI), y + s_l * -cos(fs * 2 * PI));
  }
}